An axial piston machine of this kind is known from DE 10 2006 062 065 A1 and from Bosch Rexroth AG data sheet RDE 93220-04-R/02.08, for example, and can be embodied as a single or dual axial piston machine, for example. In these known solutions, the axial piston machine is embodied with a housing in which at least one cylinder barrel having a multiplicity of pistons, each delimiting a working space, is rotatably mounted. These pistons are each supported by means of a piston foot on a swashplate, the angle of incidence of which determines the piston stroke.
The respective working space delimited by a piston can be connected alternately to a high-pressure and low-pressure duct by means of a control disk arranged at the end in the housing. The cylinder barrel is connected for conjoint rotation to a drive shaft, which acts either as an output shaft or as an input shaft, depending on the type of machine (motor, pump).
In the known solutions, the housing of the axial piston machine is of approximately cup-shaped design, wherein the high-pressure and low-pressure ducts are formed in a bottom of the cup-shaped housing and can be connected successively to the working spaces of the cylinder barrel by means of the control disk, which is fixed in relation to the rotating cylinder barrel. Formed in this control disk is a plurality of comparatively small kidney-shaped delivery openings, which lie on a common pitch circle and between which respective pressure lands are formed. On the low-pressure side, each control disk is embodied with a kidney-shaped intake opening, which extends over a larger circumferential angular range than the small kidney-shaped delivery openings.
In the region of the kidney-shaped delivery openings and of the pressure lands adjoining said openings, the high-pressure ducts are supplied with comparatively high pressures during the operation of the axial piston machine. The problem with this is that the cup-shaped housing is generally produced from spheroidal graphite iron and that, in the transition zone from the circumferential wall of the housing to the bottom region, there is a zone which is problematic in respect of the profile of the casting front, in which shrinkage cavities can occur as the casting solidifies. At high loads due to a high hydraulic pressure, damage or deformation of the housing may then occur in the region of said shrinkage cavities, thus reducing the life of the axial piston machine. These problems are more severe in the case of dual axial piston machines since the problems with casting are even more difficult to overcome, owing to the housing in the form of a dual cup.
DE 195 36 997 C1 shows a dual axial piston pump of swashplate construction in which the actual pump housing is embodied with an approximately disk-shaped central part in which the two drive shafts of the unit are connected to one another for conjoint rotation. Also mounted in this region is an impeller of a boost pump, by means of which the pressure medium can be subjected to a boost pressure on the low-pressure side. For the mounting of this impeller, the central part is embodied with an insert, which is inserted into the central part once the impeller has been mounted. High-pressure and low-pressure duct sections of a pump unit, which are assigned to one of the cylinder barrels, are formed in this insert. In the case of the second pump unit, these high-pressure and low-pressure duct sections are formed in the wall of the central part, and therefore the same problems can occur in this region as with the prior art described at the outset.
A corresponding dual axial piston pump is also described in Bosch Rexroth AG data sheet RDE 93220-04-R/02.08.
Given this situation, it is the underlying object of the disclosure to provide an axial piston machine in which the risk of damage due to pressure is reduced.
This object is achieved by an axial piston machine having the features described below. The disclosure is furthermore achieved by an insert ring in accordance with additional description below.
Advantageous developments of the disclosure form the subject matter of the below description.